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142 lines
2.8 KiB
142 lines
2.8 KiB
#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdio.h>
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typedef struct {
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char* filename; /* this file is the pipe (set by user) */
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char is_server; /* this is set by open_control_file */
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int fd; /* this is set by open_control_file */
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} single_instance_struct;
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/* returns fd, is_server is set to -1 if server, 0 if client */
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int open_control_file(single_instance_struct* str)
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{
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struct stat buf;
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if(stat(str->filename,&buf)) {
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mkfifo(str->filename,128|256);
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str->is_server=-1;
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str->fd=open(str->filename,O_NONBLOCK|O_RDONLY);
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} else {
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str->fd=open(str->filename,O_NONBLOCK|O_WRONLY);
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if(errno==ENXIO) {
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str->is_server=-1;
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str->fd=open(str->filename,O_NONBLOCK|O_RDONLY);
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} else
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str->is_server=0;
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}
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return(str->fd);
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}
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void delete_control_file(single_instance_struct* str)
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{
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remove(str->filename);
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}
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void close_control_file(single_instance_struct* str)
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{
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close(str->fd);
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}
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typedef void (*event_dispatcher)(char* message);
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int get_next_message(char* buffer,int len,single_instance_struct* str,int usecs)
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{
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struct timeval tv;
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fd_set fdset;
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int num_fds;
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FD_ZERO(&fdset);
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FD_SET(str->fd,&fdset);
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tv.tv_sec=0;
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tv.tv_usec=usecs;
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num_fds=select(str->fd+1,&fdset,NULL,NULL,&tv);
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if(num_fds) {
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int reallen;
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reallen=read(str->fd,buffer,len);
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if(reallen==0) {
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close(str->fd);
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str->fd=open(str->filename,O_NONBLOCK|O_RDONLY);
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num_fds--;
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}
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buffer[reallen]=0;
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#ifdef DEBUG_1INSTANCE
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if(reallen!=0) fprintf(stderr,"message received: %s.\n",buffer);
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#endif
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}
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return(num_fds);
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}
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int dispatch_event(single_instance_struct* str,event_dispatcher dispatcher,int usecs)
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{
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char buffer[1024];
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int num_fds;
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if((num_fds=get_next_message(buffer,1024,str,usecs)) && buffer[0])
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dispatcher(buffer);
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return(num_fds);
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}
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int loop_if_server(single_instance_struct* str,event_dispatcher dispatcher)
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{
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open_control_file(str);
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if(str->is_server) {
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while(1)
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dispatch_event(str,dispatcher,50);
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}
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return(str->fd);
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}
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void send_message(single_instance_struct* str,char* message)
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{
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#ifdef DEBUG_1INSTANCE
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int i=
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#endif
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write(str->fd,message,strlen(message));
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#ifdef DEBUG_1INSTANCE
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fprintf(stderr,"send: %s => %d(%d)\n",message,i,strlen(message));
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#endif
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}
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#ifdef DEBUG_MAIN
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#include <stdio.h>
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#include <stdlib.h>
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single_instance_struct str1 = { "/tmp/1instance" };
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void my_dispatcher(char* message)
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{
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#ifdef DEBUG_1INSTANCE
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fprintf(stderr,"Message arrived: %s.\n",message);
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#endif
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if(!strcmp(message,"quit")) {
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delete_control_file(str1);
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exit(0);
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}
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}
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int main(int argc,char** argv)
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{
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int i;
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loop_if_server(str1,my_dispatcher);
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for(i=1;i<argc;i++)
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send_event(str1,argv[i]);
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return(0);
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}
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#endif
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